USB: opticon: fix non-atomic allocation in write path

Write may be called from interrupt context so make sure to use
GFP_ATOMIC for all allocations in write.

Fixes: 0d930e51 ("USB: opticon: Add Opticon OPN2001 write support")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NJohan Hovold <johan@kernel.org>

drivers/usb/serial/opticon.c

@@ -215,7 +215,7 @@ static int opticon_write(struct tty_struct *tty, struct usb_serial_port *port,
 
 	/* The connected devices do not have a bulk write endpoint,
 	 * to transmit data to de barcode device the control endpoint is used */
-	dr = kmalloc(sizeof(struct usb_ctrlrequest), GFP_NOIO);
+	dr = kmalloc(sizeof(struct usb_ctrlrequest), GFP_ATOMIC);
 	if (!dr) {
 		count = -ENOMEM;
 		goto error_no_dr;